Preheat the oven to 350F (177C). Line the bottom of two, 8-inch (20-cm) round cake pans with parchment paper; leave the sides ungreased.
Prepare the coffee sponge cake first. In a stand mixer bowl, whisk together the eggs and sugar on high speed for 7 to 8 minutes, until the eggs are thick, voluminous and pale in color. In a small ramekin or bowl, dissolve the 1 tablespoon instant coffee powder in 2 tablespoons boiling water. Pour the dissolved coffee into the eggs and mix again for 30 seconds.
In a separate bowl, combine the dry ingredients: flour, almond flour and baking powder. Sift the dry ingredients into the eggs in small batches, folding gently but thoroughly after each addition. Divide the batter evenly between the two pans.
Bake the layers in the preheated oven for 33 to 35 minutes, until the tops are set. Remove the layers from the oven and allow them to cool completely in the pan. Once layers are cooled, run a knife along the edge of the pan to release the cake. Use a long serrated knife to split each layer in half, resulting in four layers total.
Preparing the Milk Syrup:
For the coffee syrup, first heat the milk in a microwave safe measuring cup until the milk is steaming hot. Add the instant coffee and stir until it’s dissolved. Add the sweetened condensed milk, evaporated milk, then stir until all three milks are well combined; set aside.
Making the Frosting:
Next, prepare the coffee whipped cream. In a small bowl, dissolve the instant coffee in the boiling water. Allow the coffee to cool. Add the dissolved coffee into a large mixing bowl along with the softened cream cheese (or chilled mascarpone) and sugar.
Whisk the ingredients together for a few minutes until completely smooth and creamy. Add in the chilled heavy cream and whisk again until stiff peaks form, about 3 to 5 minutes. The frosting should be fluffy and hold its shape.
Assembling the Cake:
Before assembling the cake, make sure the cake layers are completely cooled! Start by soaking each sponge cake layer very generously with the prepared coffee milk syrup, then frost with whipped cream.
Frost the top and sides with a flat spatula. Transfer any remaining cream into a pastry bag tipped with a simple round tip; garnish the top of the cake with dollops of cream. Sprinkle the top with cocoa powder and add whole coffee beans, if desired.